Geological observations on the Kirkpatrick Basalt in the Mesa Range ...

Maximum ground temperatures measured in warm ground areas in 1972 (after Lyon and Giggenbach 1974) and 1983

Warm ground area 2

Warm ground area 1

Date



Maximum temperature measured (©C)

Depth of measurement (in centimeters)

Maximum temperature measured ( CC)

Depth of measurement (in centimeters)

20, 21

January 1983

+20.5



15

58.0

10

15

59.0

25

15, 16

December 1972

+21.0



This work was supported by the captain, officers, and crew of during Deep Freeze 83, to whom we are most grateful. The research was supported by National Science Foundation grants DPP 80-20002 and DPP 80-21402. Field personnel for this study were J . R. (Harry) Keys and W. C. McIntosh; they were in the field 20-21 January 1983. USCGC Glacier

References Adamson, R. C., and R. J. Cavaney. 1967. Volcanic debris-layers near Mt. Melbourne, northern Victoria Land, Antarctica. New Zealand

Geological observations on the Kirkpatrick Basalt in the Mesa Range region, northern Victoria Land D. H. ELLIOT, C. FAURE, T. M. MENSING, M. A. SIDERs, M. A. HABAN, and E. M. CHERRY Institute of Polar Studies Department of Geology and Mineralogy The Ohio State University Columbus, Ohio 43210

A second season of fieldwork was conducted in the general area of the Mesa Range between 12 November and 17 December 1982 (see figure). The objectives for the 2-year field program included making stratigraphic studies; sampling for petrological, mineralogical, geochemical, and isotopic studies; and collecting rocks for paleomagnetic investigations. Stratigraphic sections were measured at Mills Valley, Mount Ballou, and Mount Masley on Pain Mesa; on Tobin Mesa; and on 1983 REVIEW

Journal of Geology and Geophysics, 10(2), 418-421. Giggenbach, W. F. 1976. Geothermal ice caves on Mt. Erebus, Ross Island, Antarctica. New Zealand Journal of Geology and Geophysics, 19(3), 365-372. Lyon, C. L., and W. F. Giggenbach. 1974. Geothermal activity in Victoria Land, Antarctica. New Zealand Journal of Geology and Geophysics, 17(3), 511-521. Nathan, S., and F. J. Schulte. 1967. Recent thermal and volcanic activity on Mt. Melbourne, northern Victoria Land, Antarctica. New Zealand Journal of Geology and Geophysics, 10(2), 422-430. Nathan, S., and F. J. Schulte. 1968. Geology and petrology of the Campbell Aviator Divide, northern Victoria Land, Antarctica. Part 1—Post Paleozoic rocks. New Zealand Journal of Geology and Geophysics, 11,

940-975.

Sculpture Mountain. The basal part of the basalt sequence and the contact with the underlying rocks were examined at Agate Peak, Mount Fazio, the Exposure Hill area, and in the upper reaches of the Aeronaut Glacier. Diabase intrusions crop out in the latter two areas. The maximum stratigraphic thickness of the Kirkpatrick Basalt is estimated to be 900 meters. A small number of flows in the Mesa Range can be used as stratigraphic markers to correlate the lower part of the section. A unit of black basalt which forms a prominent feature in the Mesa Range is also present on Sculpture Mountain and will facilitate the correlation of the basalt sequences between the mesas and scattered nunataks of the upper Rennick Glacier region. The basalts rest on volcanic breccias and volcanogenic sedimentary rocks that appear to be similar to the Mawson Diamictite of southern Victoria Land (Ballance and Watters 1971; Hall, Sutter, and Borns 1982). These deposits were observed at the base of Tobin Mesa, at the southern end of Gair Mesa, and at the head of the Aeronaut Glacier. At each of these locations, the Kirkpatrick Basalt disconformably overlies the volcaniclastic rocks. At the southern end of Gair Mesa a sedimentary interbed containing conchostracans is present near the base of the basalt sequence. The Agate Peak locality, first described by Nathan 11



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basalt sequence. Tree stumps in situ were noted at several places. Observations during this field season support the conclusion, tentatively drawn last season (Elliot et al. 1982), that there is no compelling evidence for major faulting at the head of the Rennick Glacier between Exposure Hill and Vantage Hills. Nevertheless, a fault probably separates Sheehan Mesa from outcrops to the west and significant faulting undoubtedly occurs to the north, along the Rennick Glacier. Petrographic examination and laboratory studies of the major and trace element composition of basalts and diabases, of the mineral chemistry, and of the isotopic composition of these rocks are in progress. Dating of the basalts by the argon-40/ argon-39 technique will also be attempted. The basalts and diabases will be used to determine a paleomagnetic pole position, to establish a record of magnetic polarity reversals, and to study the magnetic properties of the minerals. This study was supported by National Science Foundation grant DPP 80-21401.

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Location and geologic sketch map for the Mesa Range region of northern Victoria Land.

and Schulte (1968), was reexamined but no new fossil material was collected during the 1982-1983 field season. Interbeds composed of volcaniclastic debris occur at numerous localities throughout the Mesa Range, principally in the lower part of the

Petrogenesis of the Kirkpatrick Basalt, Solo Nunatak, northern Victoria Land TERESA M. MENSING, GUNTER FAURE, and KAREN S. TAYLOR Institute of Polar Studies The Ohio State University Columbus, Ohio 43210

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Ballance, P. F., and W. A. Watters. 1971. The Mawson Diamictite and Carapace Sandstone, formations of the Ferrar Group at Allan Hills and Carapace Nunatak, Victoria Land, Antarctica. New Zealand Journal of Geology and Geophysics, 14, 512-527. Elliot, D. H., M. Siders, G. Faure, and K. S. Taylor. 1982. The Kirkpatrick Basalt, Mesa Range, northern Victoria Land. Antarctic Journal of the U.S., 17(5), 19--20. Hall, B. A., J. F. Sutter, and H. W. Borns. 1982. The inception and duration of Mesozoic volcanism in the Allan Hills—Carapace Nunatak area, Victoria Land, Antarctica. In C. Craddock (Ed.), Antarctic geoscience, Madison: University of Wisconsin Press. Nathan, S., and F. J . Schulte. 1968. Geology and petrology of the Campbell-Aviator Divide, northern Victoria Land, Antarctica. New Zealand Journal of Geology and Geoph ysics, 11, 960-975.

Anomalously high initial strontium-87/strontium-86 (87Sr/86Sr) ratios (greater than 0.710) for the Jurassic tholeiites (approximately 170 million years old) of the Transantarctic Mountains have been well documented by Compston, McDougall, and Heier (1968); Faure (1981); Faure, Bowman, and Elliot (1979); Faure et al. (1972, 1974); Hoefs, Faure, and Elliot (1980); Kyle (1980); and Kyle, Elliot, and Sutter (1980). These rocks of the Ferrar Supergroup extend from northern Victoria Land to the Pensacola Mountains and are composed of dolerite intrusions (Ferrar Dolerite Group) and basalt lava flows (Kirkpatrick Basalt Group). Major element data for these rocks display normal differentiation trends when plotted on variation diagrams. That is, positive correlations exist between Si0 2 and Na2O, K20, Ti02, and P205 (Kyle 1980). Negative correlations are observed between S'02 and calcium oxide (CaO), magnesium oxide (MgO), and aluminum oxide (Al 20) (Kyle 1980). Two petrogenetic models have been proposed to explain the observed isotopic and chemical trends for these rocks: (1) contamination of mantle-derived melts by the assimilation of crustANTARCTIC JOURNAL